1. Field of the Invention
The present invention generally relates to a portable terminal such as a cellular phone, a smart phone or a tablet PC, and more particularly, to a portable terminal provided with a wireless charging module.
2. Description of the Related Art
A portable terminal, such as a mobile communication terminal such as a cellular phone, a smart phone or the like, is incorporated with more and more functions as multimedia services continue to expand. In addition, as various application programs are provided, the functions of the portable terminal are increasing more rapidly and user interface environments are being developed to be conveniently used as well as to satisfy various users' tastes and needs.
Portable terminals may be classified into, for example, a bar-type terminal, a folder-type terminal, a sliding-type terminal, and a swing-type terminal according to the external appearances thereof. When mobile communications such as voice communications and short message transmissions were principal functions, folder-type terminals or slider-type terminals occupied a great part of the market. However, as the multimedia services have been developed as described above, the necessity of enlarged display devices of portable terminals has increased. Accordingly, as the display devices of portable terminals have been enlarged recently, physical keypads tend to be removed from the portable terminal by incorporating a touch screen function in the display devices. The portability of a portable terminal is improved by providing a touch screen device to remove a physical keypad so that a display device may be enlarged and a thickness of a portable terminal is reduced.
In addition, a portable terminal is provided with antenna devices that enable communication in various frequency bands such as a DMB (Digital Multimedia Broadcasting) antenna, a LAN (Local Area Network) antenna, an NFC (Near Field Communication) antenna, a Bluetooth antenna and the like in addition to an antenna device for a wireless communication function. Recently, beyond such antenna devices, a portable terminal is equipped with an antenna and a module that provides a mobile charging function.
FIG. 1 is an exploded perspective view illustrating a portable terminal 100 according to the prior art. In particular, FIG. 1 illustrates a configuration provided with a wireless charging module that includes a receiving-side resonant antenna 131 that provides a wireless charging function and a receiving circuit unit provided on a substrate 133.
As illustrated in FIG. 1, the terminal 100 includes a battery mounting groove 119 formed on a back surface of a body 101, and a camera module 117 provided at a side of the battery mounting groove 119. The battery mounting groove 119 is concealed by a cover member 102 detachably provided on the back surface of the body 101. A user may access the battery mounting groove 119 by removing the cover member 102 as needed. In addition, the cover member 102 is provided with an opening 127 that exposes the camera module 117 so that a subject may be photographed even when the cover member 102 is coupled to the body 101.
The cover member 102 is provided with a wireless charging module 130 on the inner surface thereof. The wireless charging module 130 includes a receiving-side resonant antenna 131 and a receiving circuit unit. A second cover member 141 may be provided on the inner surface of the cover member 102 so as to provide a stable installment structure of the receiving-side resonant antenna 131 and the receiving circuit unit.
The receiving-side resonant antenna 131 may produce a signal power by a magnetic induction or magnetic resonance phenomenon according to an electromagnetic field generated at a primary coil of a charger (not illustrated) and transmits the signal power to the receiving circuit unit. A connection piece 131a connected to the receiving circuit unit is formed at a side of the receiving-side resonant antenna 131. The receiving-side resonant antenna 131 is configured to be attached to the inner surface of the cover member 102. In the portable terminal 100 illustrated in FIG. 1, the second cover member 141 is coupled to the cover member 102 when the receiving-side resonant antenna 131 is attached to the inner surface of the second cover member 141. As a result, the receiving-side resonant antenna 131 is disposed on the inner surface of the cover member 102.
The terminal 100 is provided with an electromagnetic shielding member 139 in order to reduce or eliminate an effect exerted on circuit devices inside the body or a battery pack by the electromagnetic field formed around the receiving-side resonance antenna 131. The electromagnetic shielding member 139 is attached on the cover member 102 and interposed between the receiving-side resonant antenna 131 and the body 102. As mentioned above, since the receiving-side resonant antenna 131 is directly attached to the second cover member 141, the receiving-side resonant antenna 131 may be attached on the electromagnetic shielding member 139 after the electromagnetic shielding member 139 is attached to the second cover member 141 in advance.
Since the receiving circuit unit includes the wireless charging circuit provided on the substrate 133, the receiving circuit unit converts a signal power received through the receiving-side resonant antenna 131 into a charging power and provides the charging power to the battery pack mounted on the body 101. A connection portion 131b corresponding to the connection piece 131a is provided at a side of the substrate 133. The receiving circuit unit is also attached to the second cover member 141 together with the receiving-side resonant antenna 131. When the receiving-side resonant antenna 131 and the receiving circuit unit are attached to the second cover member 141, the connection piece 131a and the connection portion 131b are engaged with each other to be electrically connected.
A flexible printed circuit board 135 is disposed at a side of the receiving circuit unit and a connection pad 137 is provided at an end of the flexible printed circuit board 135. The charging power provided from the receiving circuit unit is transmitted to the body 101 through the flexible printed circuit board 135 and the connection pad 137. The body 101 is provided with connection terminals 115 provided at a side of the battery mounting groove 119 and, when the cover member 102 is coupled to the body 101, the connection pad 137 is connected with the connection terminals 115, thereby providing the charging power to the body 101, in particular, to the battery pack mounted on the body 101.
FIG. 2 schematically illustrates a configuration of the wireless charging module disposed on the cover member 102. FIG. 2 describes the height h of the wireless charging module 130, i.e. the thickness. It is noted that the second cover member 141 is not illustrated and the wireless charging module 130 is illustrated as being configured to be directly attached to the cover member 102.
The receiving-side resonance antenna 131 and the electromagnetic shielding member 139 are stacked on the inner surface of the cover member 102 and the receiving circuit unit includes circuit elements 133a, such as a charging control circuit chip and an inductor which are mounted on the substrate 133. The thicknesses of the receiving-side resonant antenna 131 and the substrate 133 are about 0.35 mm, the thickness of the electromagnetic shielding member 139 is about 0.6 mm, and the maximum height of the circuit elements 133a is about 1.25 mm. Accordingly, the maximum thickness of the wireless charging module 130 from the inner surface of the cover member 102 is about 1.6 mm.
As described above, as the multimedia functions of portable terminals have been developed, display devices have been enlarged and efforts are continuing to reduce the thickness of the portable terminals as well as the weight of the portable terminals, for portability. However, a wireless charging module may make it convenient to charge a portable terminal but increases the thickness of the portable terminal. Especially, since portable terminals having a thickness of not more than 10 mm prevails according to the tendency of slimming portable terminals, equipping a wireless charging module having a thickness of 1.6 mm in a portable terminal will cause a result of going against trend of the slimming of portable terminals.
In addition, when the receiving-side resonant antenna or the receiving circuit unit is positioned to face the battery pack, there is a problem in that the thickness of the portable terminal is further increased. The battery pack is rectangular and has a predetermined volume. Therefore, when the receiving-side resonant antenna or the like is positioned to face the battery pack, a predetermined thickness of the portable terminal should be secured in order to secure a space capable of accommodating the receiving-side resonant antenna or the like.